A method for friction stir welding two components, with a rotating tool that comprises a rotating or non-rotating shoulder surface for subjecting the components to a process force in the region of a joining zone, and with a stirring pin for stirring plasticized material or for plasticizing and stirring the components in the region of the joining zone, in which method a stirring pin with a section slidably plunges in a slide on which the components are supported, which slide is guided along the joining zone on a side of the component, which side faces away from the tool, so that during welding an automatic relative movement between the stirring pin and the slide or the shoulder surface of the tool and a support surface of the slide, which support surface supports the components, is made possible, as well as a device for implementing such a method.